Concave Adjustment Mechanism

ABSTRACT

A combine harvester where opposing concaves on either side of a rotor of a processing system substantially simultaneously travel symmetrical paths. The concaves of the processing system may be pivotally supported on a rockshaft where the axis of the rockshaft moves in a generally vertical manner so that the concaves then move generally radially toward or away from the rotor.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present U.S. application is related to U.S. application entitled“COMBINE HARVESTER PROCESSING SYSTEM HAVING ADJUSTABLE CONCAVES ON ASUSPENSION SYSTEM” (A1023H), which is incorporated herein by reference,and having been filed concurrently with the present application.

TECHNICAL FIELD

This invention relates to the crop processing systems of combineharvesters.

BACKGROUND

In one type of processing system the crop travels axially parallel toand helically around the rotational axis of one or more rotaryprocessing devices commonly referred to as rotors. In other systems,during at least a portion of its travel through the system the croptravels in a transverse or tangential direction relative to therotational axis of a rotary processing device commonly referred to as athreshing cylinder. In each case, grain is processed between elementsaffixed to the periphery of the rotary device and arcuate, usuallyforaminous, stationary processing members in the form of threshingconcaves or separating grates that partially wrap around the lowerportion of the device.

Because processing systems are utilized to harvest a wide variety ofdifferent crops and must function properly in many different operatingconditions, it is important to be able to conveniently and accuratelyadjust the running clearance in the region between the rotary processingdevices and stationary processing members to best accommodate thesevariables. However, it is also important to provide a way of suitablychanging the cross-sectional shape of such regions as the runningclearance is adjusted whereby to assure that proper processing action isobtained throughout the range of adjustment. While systems using axialflow have somewhat different specific requirements from system usingtransverse flow due to their different principles of operation, they canboth benefit from an ability to appropriately adjust the cross-sectionalshape of their processing regions as the running clearance is increasedor decreased.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side elevational view of a combine harvesterhaving a processing system utilizing axial flow and incorporating theprinciples of the present invention, portions of the harvester beingbroken away to reveal internal details of construction;

FIG. 2 is a side view of a concave of the processing system within theharvester of FIG. 1 according to one embodiment of the presentinvention;

FIG. 3 is a left side isometric view of the concave of FIG. 2 accordingto an alternative embodiment;

FIG. 4 is a left side isometric rear view of a guide assembly of asuspension system within the combine harvester of FIG. 1 according toone embodiment of the present invention;

FIG. 5 is an exploded view of the guide assembly of FIG. 5 according toone embodiment of the present invention;

FIG. 6 is a left rear isometric view of the processing system in theopen position without the rotor according to one embodiment of thepresent invention;

FIG. 7 is a front elevational view of the processing system of FIG. 6;

FIG. 8 is a left rear isometric view of the processing system similar toFIG. 6 but illustrating the concaves in their fully closed positionminimizing the running clearance between the rotor and the concaves;

FIG. 9 is a front elevational view of the processing system of FIG. 8;

FIG. 10 is a close-up isometric view from underneath the processingsystem of the front guide and the rockshaft with the concaves in theclosed position according to one embodiment of the present invention;

FIG. 11 is a close-up rear isometric view of the rear guide and therockshaft with the concaves in the closed position according to oneembodiment of the present invention;

FIG. 12 is a close-up rear view of the opposite side of the rear guideand the rockshaft with the concaves in the closed position according toone embodiment of the present invention;

FIG. 13 is a rear elevational view of the processing system similar toFIG. 7 but illustrating substantially equal gaps of a distance d betweenthe concaves in their fully open position and the rotor when maximizingthe running clearance between the rotor and the concaves; and

FIG. 14 is a graph illustrating the distance d of the gaps between theconcaves and the rotor as the concaves move over time.

DESCRIPTION OF EXAMPLE EMBODIMENTS

The present invention is susceptible of embodiment in many differentforms. While the drawings illustrate and the specification describescertain preferred embodiments of the invention, it is to be understoodthat such disclosure is by way of example only. There is no intent tolimit the principles of the present invention to the particulardisclosed embodiments. References hereinafter made to certaindirections, such as, for example, “front”, “rear”, “left” and “right”,are made as viewed from the rear of the harvester looking forwardly.

The exemplary combine harvester 10 selected for illustration in FIG. 1has a single axial flow processing system 12 that extends generallyparallel with the path of travel of the machine. However, as will beseen, the principles of the present invention are not limited toharvesters with processing systems designed for axial flow, nor to axialflow harvesters having only a single such processing system. However,for the sake of simplicity in explaining the principles of the presentinvention, this specification will proceed utilizing a single axial flowprocessing system as the primary example.

As well understood by those skilled in the art, in the illustratedembodiment combine harvester 10 includes a harvesting header (not shown)at the front of the machine that delivers collected crop materials tothe front end of a feeder house 14. Such materials are moved upwardlyand rearwardly within feeder house 14 by a conveyer 16 until reaching abeater 18 that rotates about a transverse axis. Beater 18 feeds thematerial upwardly and rearwardly to a rotary processing device, in thisinstance to a rotor 22 having an infeed auger 20 on the front endthereof. Auger 20, in turn, advances the materials axially into theprocessing system 12 for threshing and separating. In other types ofsystems, conveyor 16 may deliver the crop directly to a threshingcylinder.

Generally speaking, the crop materials entering processing system 12move axially and helically therethrough during threshing and separating.During such travel the crop materials are threshed and separated byrotor 22 operating in cooperation with preferably foraminous processingmembers in the form of threshing concaves 24 and separator grateassemblies 26, with the grain escaping laterally through concaves 24 andgrate assemblies 26 into cleaning mechanism 28. Bulkier stalk and leafmaterials are retained by concaves 24 and grate assemblies 26 and areimpelled out the rear of processing system 12 and ultimately out of therear of the machine. A blower 30 forms part of the cleaning mechanism 28and provides a stream of air throughout the cleaning region belowprocessing system 12 and directed out the rear of the machine so as tocarry lighter chaff particles away from the grain as it migratesdownwardly toward the bottom of the machine to a clean grain auger 32.Auger 32 delivers the clean grain to an elevator (not shown) thatelevates the grain to a storage bin 34 on top of the machine, from whichit is ultimately unloaded via an unloading spout 36. A returns auger 37at the bottom of the cleaning region is operable in cooperation withother mechanism (not shown) to reintroduce partially threshed cropmaterials into the front of processing system 12 for an additional passthrough the system.

The combine includes a framework around the processing system 12 thatpreferably includes a front bulkhead and a center bulkhead where theconcaves 24 are supported between the front and center bulkheads. Thegrates 26 are preferably supported between the center bulkhead and arear bulkhead. As shown in FIG. 1 both the concaves 24 and grateassemblies 26 together concentrically receive the rotor 22 to serve aspart of processing system 12. A pair of opposite facing, end-to-endconcaves 24, which are the forwardmost concaves 24, are illustrated inFIGS. 6-9. However, it is preferable that the processing system 12includes six pairs (total of twelve) substantially identical concaves 24coupled within the combine 10 with one concave of each pair of concaves24 positioned side-by-side along one side of the rotor 22 and the otherconcave of each pair of concaves 24 positioned side-by-side on theopposite side of the rotor 22. The concaves 24 are preferably of similaror substantially identical construction as described in greater detailbelow.

One or more concaves 24 include a cradle-like frame having a pair ofarcuate, elongated and laterally spaced apart side rails 40 as bestshown in FIGS. 2 and 3. Each concave 24 includes a plurality oftransverse bars 42 that span the side rails 40. The transverse bars 42cooperate with a series of longitudinally extending, laterally spacedapart, curved rods 46 in defining apertures for the concave 24 throughwhich grain may pass. The upper edges of transverse bars 42 projectabove the longitudinally extending curved rods 46 so as to provide astepped threshing surface that cooperates with rasp-like elements on therotating rotor 22 for threshing and separating the grain from cobs,husks, and other crop materials. The width of concave 24 is such that aplurality of concaves 24 can be installed side-by-side in the combine 10and so that projecting overhangs at ends of one or more of thetransverse bars 42 are operable to bear against each between adjacentconcaves 24 are installed side-by-side in the combine. The overhangs ofeach transverse bar 42 also provide a continuous surface when theconcaves 24 are installed side-by-side in the combine.

In one or more embodiments, a pair of laterally spaced transverse endswalls 48 extend between the side rails 40 and are rigidly affixedthereto. In another embodiment, an endmost transverse bar 52 can act asan end wall. As best shown in FIG. 4, at an upper end of the concave 24,the end wall 48 includes one or more mounting holes to be aligned withmounting holes in an axially extending support members, such as anglemembers 52, 54 so that the concaves 24 can be securely mounted at theiruppermost ends with fasteners.

Although the combine 10 may also include separator grate assemblies 26,none of the grate assemblies 26 are mounted for adjusting movement in aradial direction toward and away from rotor 22 in the particularillustrated embodiments, it is within the principles of the presentinvention to make grates 26 adjustable in the same manner as concaves24. In the illustrated embodiments, each separator grate 26 is fixed toframework surrounding the rotor 22.

Each concave assembly 24 wraps around a portion of the bottom of rotor22 in a circumferential direction and is adapted to move generally in asubstantially symmetrical and concentric manner toward and away fromrotor 22. A distal portion of each side rail 40 of each concave 24extends outward beyond the endmost transverse bar 42 so that the lowerend of each concave 24 may be received and carried by an axial extendingcommon support assembly 60.

In one embodiment, as best shown in FIG. 3, the common support assemblyincludes a common axial shaft such as a fore-and-aft extending rockshaft62 below the rotor 22. Preferably the rockshaft 62 is a machine shaftdesigned to rock back and forth. The rockshaft 62 may also have asupport member 66 along its length on its underside if additionalrigidity is desired as best shown in FIGS. 6, 8 and 10-12.

Preferably, the distal ends of one or more side rails 40 includeshook-shaped lugs 70 so that the hook-shaped lugs 70 rest on top of therockshaft 62. At least a portion of the shape of each lug 70 conforms toat least an upper portion of the circumference of the elongated supportbar 62. Preferably the inner diameter of the lug 70 substantiallyconforms to a portion of the outer diameter of the rockshaft 62. Whenthe concaves 24 move toward or away from the rotor 22, the distalportions of the side rails 40 rotate about a portion of thecircumference of rockshaft 62.

As best shown in FIG. 3, the support assembly 60 includes anotherelongated shaft 76 so that the distal portions of the side rails 40 ofthe concaves may be received between the rockshaft 62 upon which theconcaves 24 rest and the other elongated shaft 76 which acts to retainthe distal ends of the side rails 40. Both the rockshaft 62 and theelongated shaft 76 of the common support assembly 60 may be pivotallyaffixed to one another by spacing members such as tie straps 78extending therebetween. In such case, the tie straps 78 are configuredto define a first aperture sized for receiving the rockshaft 62therethrough and define a second aperture sized for receiving theelongated shaft 76 therethrough. Preferably the elongated shaft 76 isfixed within the second aperture of each tie strap 78.

The concave assemblies 24 are moved adjustably toward and away fromrotor 22 by operating mechanism broadly denoted by numeral 80. Operatingmechanism 80 functions to substantially simultaneously adjust the pairof opposite facing concaves 24 relative to rotor 22 so as to adjust therunning clearance between rotor 22 and concaves 24 and to change theshape of the threshing region. The primary component of operatingmechanism 80 is an actuator 82 located near the left front of processingsystem 12 and is preferably coupled to a spring 56 mounted with abracket 58 on the forward bulkhead 84, but may be located elsewhere.Preferably, actuator 82 is remotely operable, such as from the cab ofharvester 10. In one preferred embodiment, actuator 82 comprises anelectrically powered linear actuator. However, that actuator 82 couldcomprise a number of different devices, such as a hydraulic cylinder ora turnbuckle, for example.

A rod 68 coupled to the spring 56 extends to a linkage 72 which pivotsabout fixed pivot point 73. The lever 90 pushes actuator 82 upward whenthe concaves 24 are moved away from the rotor 22. Thus, the operatingmechanism 80 with actuator 82 may be moved up to permit the concaves 24to shift downward away from the rotor 22 if a foreign object or anexcessive amount of crop flow is ingested by the processing system 12.Preferably an adjustable nut at the top of the rod 68 on top of thespring 56 controls how close the operating mechanism 80 is allowed tolet the concaves 24 get to the rotor 22. When the large load orobstruction enters at the front of the processing system 12, the rod 68is moved upward to compress the spring 56 to accommodate the large loador obstruction. As the large load or obstruction proceeds through theprocessing system 12 toward the rear of the combine 10, the spring 56 iscompressed to accommodate the large load or obstruction. Thus, as thelarge load or obstruction passes from the front to the rear of theprocessing system, the operating mechanism 80 with actuator 82compresses the spring 56 so that the concaves 24 may move away from therotor 22. Thus, each pair of concaves 24 coupled to the angle members52, 54 along the length of the processing system 12 is able to beadjusted to accommodate the large load or obstruction.

A control rod 88 of actuator 82 is connected pivotally coupled at itsend to an end of lever 90 that also forms a part of operating mechanism80. The lever 90 is also pivotally coupled at its other end to therockshaft 62. Rockshaft 62 is journaled at its ends for rotation withina guide such as guide plates 92. A guide plate 92 is connected to theforward bulkhead 84 and also the center bulkhead 98 of the combineframework. Preferably, each end of the rockshaft 62 is journaled inguide blocks 94 configured to translate in substantially vertical guideslots 96 in the guide plates 92. The guide slots 96 are substantiallyvertically oriented so that the movement of the rockshaft 62 in theguide slots 96 raises and lowers the pair of concaves 24 relative therotor 22. However, the rockshaft 62 may be supported by any meanspossible which is suitable for allowing the rockshaft 62 to rotate aswell as translate as a result of movement initiated by the operatingmechanism 80.

The guide plates 94 also include substantially horizontal guide slots102 for receiving and retaining a second set of guide blocks 104. Thelever 90 also is pivotally coupled to one of the guide blocks 104. Whenthe actuator 82 is actuated, movement of the lever 90 causes the guideblocks 104 to translate in the guide slots 102 and the guide blocks 94to translate in guide slots 96 which raises and lowers the pair ofconcaves 24 relative the rotor 22. Preferably both sets of guide blocks94, 104 slide in their respective guide slots 96, 102. However, it iswithin the scope of this invention that the guide blocks 94, 104 mayalso roll in said guide slots 96, 102. Also, although the presentinvention describes substantially vertical and horizontal slots 96, 102,the guide slots may be oriented differently relative to one another solong as the pair of concaves 24 may be raised and lowered relative therotor 22 in a symmetrical and concentric manner.

FIGS. 6 and 7 illustrate the pair of concaves 24 in a fully openposition relative the rotor 22 when the rod 88 of the actuator 82 is notextended and the lever 90 therefore urges the blocks 104 to the left inguide slots 102 of guide plates 92 when viewed from the rear of thecombine 10. Also, the guide blocks 94 are urged into their lowermostposition in guide slots 96 by the lever 90.

FIGS. 8-12 illustrate the pair of concaves 24 in a fully closed positionrelative the rotor 22 when the rod 88 of the actuator 82 is extended.The lever 90 therefore urges the blocks 104 to the right in guide slots102 of guide plates 92 when viewed from the rear of the combine 10.Also, the guide blocks 94 are urged into their uppermost position inguide slots 96 by the lever 90. FIG. 10 illustrates a close-up view ofthe forward guide plate 92 from underneath the processing system 12 andthe positions of the guide blocks 94, 104 in their respective guideslots 96,102 when the concaves 24 are raised into the closed position.FIG. 11 illustrates a close-up view of the rear guide plate 92 and thepositions of the guide blocks 94, 104 in their respective guide slots96,102 when the concaves 24 are raised into the closed position. As bestshown in FIG. 12 from underneath and at the rear of the processingsystem 12, a link 86 is pivotally coupled to the guide block 94 and theguide block 104 with rockshaft 62 such that the guide blocks 94, 104 inthe rear guide plate 92 cooperate and respond with one another in theirmovement as do the guide blocks 94, 104 in the forward guide plate 92with the lever 90.

One or more guide assemblies 106 each define a guide slot 108.Preferably there are two oppositely spaced guide assemblies 106 at thefront of the processing system 12 affixed to the backside of the forwardbulkhead 84 on opposite sides of the rotor 22. Another two oppositelyspaced guide assemblies 106 are affixed to the front of the centerbulkhead on opposite sides of the rotor 22. The guide slot 108 definedby each guide assemblies 106 is configured to permit generally up anddown sliding movement of the support members 52, 54. The guide slots 108may receive and retain a stop block 110 such as a plastic or rubber stopblock on an arm 112 which are coupled to the angle members 52, 54 andcooperate with the guide assemblies 106 when received and retained inthe guide slots 108 so that the range of up and down motion is limited.Alternatively, a bearing may be coupled to the angle members 52, 54 tobe received and retained in the guide slots 108 while rolling in theguide slots 108.

Preferably, as best shown in FIG. 5, the guide assemblies 106 have afirst portion 114 and a second portion 116 that cooperate with oneanother when assembled together to define the guide slot 108. The firstportion 114 includes an upturned portion 120 that defines one side ofthe guide slot 108 and the second portion 116 includes another upturnedportion 122 that defines the opposite side of the guide slot 108. Whenthe first portion 114 and second portion 116 are assembled together thesecond portion 116 overlaps the first portion 114 so that mounting holesin each portion are aligned to receive fasteners to affix the guideassemblies 106 to the respective bulkhead. In one embodiment, ends 124,126 of the up turned portion 122 of the second portion 116 are turnedinward to substantially become parallel to one another and define theupper and lower translational limits of the guide slot 108.

As best shown in FIGS. 6-12, movement of the operating mechanism 80causes the common support assembly 60 to move along a generally verticaldirection. The lugs 70 of each concave 24 are pivotally mounted on therockshaft 62 which allows the concaves 24 to shift as they are movedtoward or away from the rotor 22. The guide assemblies 106 and the guideplates 92 cooperatively maintain the concaves 24 in a substantiallyconcentric relationship relative to the rotor 22. Consequently, whenactuator 82 extends and retracts, motion is imparted to rockshaft 62which in turn allow the concaves to simultaneously pivot upon therockshaft 62 and slide in guide slots 108. The combination of thepivoting and sliding action causes the threshing region between rotor 22and the pair of concaves 24 to be reshaped appropriately as the runningclearance is adjusted.

As illustrated in FIGS. 7 and 9, rotor 22 rotates in a counter-clockwisedirection as viewed from the front of the combine 10. Thus, as cropmaterials are introduced into the front end of processing system 12,they move helically within and about the rotor housing in acounter-clockwise direction. The threshing action occurs in a threshingregion located generally in the bottom half of the processing system 12,between the periphery of rotor 22 and concave assemblies 24.

When actuator 82 is extended, the concaves 24 are substantiallysimultaneously moved inwardly toward rotor 22 as best shown in FIG. 9. Aconverging, generally wedge-shaped inlet to the threshing region forcrop materials coming around rotor 22 is denoted broadly by the numeral158. The wedge-shaped inlet 158 tapers in the direction of rotation atone end of the threshing region. An opposite, diverging, generallywedge-shaped outlet from the threshing region is denoted by the numeral160. A gap at the top of the pair of concaves 24 is greater than the gapat the bottom of the pair of concaves 24 when the pair of concaves 24are in the closed position relative the rotor 22 such that thewedge-shaped inlet 158 and the wedge-shaped outlet 160 are generallydefined between the pair of concaves 24 and the rotor 22.

In the illustrated embodiment, in the minimum clearance position of FIG.7 the concaves 24 are concentric with rotor 22 over an arc ofapproximately sixty degrees on opposite sides of and symmetrical withthe common support assembly 60. To increase threshing and separatingaggressiveness, the area of concentricity could be extendedsignificantly beyond sixty degrees such as, for example, to one hundredtwenty degrees.

As the concaves 24 are adjusted toward the fully open position, thethreshing region is simultaneously reshaped to thereby decrease theaggressiveness of the threshing action in that area. While the concaves24 of each pair of concaves 24 are moved away from rotor 22 no more thanapproximately seventy-five percent of full open adjustment, the pair ofconcaves 24 and the rotor 22 remain substantially concentric and gapsbetween the pair of concaves 24 and the rotor 22 are substantially thesame at the top of the pair of concaves 24 and at the bottom of the pairof concaves 24. In the event the rotor 22 needs to be unplugged, theoperator may adjust the concaves 24 beyond seventy-five percent into amore fully open position so that the concaves 24 go beyond concentricitywhich allows the operator the ability to unplug the rotor 22. Whenmoving the concaves 24 between fully open and fully closed positions,the concaves of the pair of concaves 24 travel a symmetrical pathrelative to one another.

FIG. 13 is a rear elevational view of the processing system 12 similarto FIG. 7. FIG. 13 illustrates substantially equal gaps of a distance dbetween the concaves 24 in their fully open position and the rotor 22when maximizing the running clearance between the rotor 22 and theconcaves 24. The top right and left distances, as well as the bottomright and left distance are all approximately the same distance d. FIG.14 is a graph illustrating the distance d of the gaps between theconcaves 24 and the rotor 22 as the concaves 24 move over time from aclosed position into an open position. When the concaves 24 are in thefully closed position, as about zero seconds, the bottom right and leftdistances (represented by the lower line) approach approximately zerowhereas the top right and left distances (represented by the upper line)are approximately between 20 and 30 millimeters. The graph of FIG. 14also illustrates that the distances between the top right and left aswell as the bottom right and left converge over time. Betweenapproximately 30 and 40 millimeters the distance between the top rightand left as well as the bottom right and left should be measured atabout the same distance d as the concaves approach an open position, ofapproximately seventy-five percent of fully open, for optimallyoperating the processing system 12 for processing crops. In the example,the concaves 24 took approximately 15 seconds to reach the fully openposition with a distance d of approximately 35 mm between the top rightand left as well as the bottom right and left.

The foregoing has broadly outlined some of the more pertinent aspectsand features of the present invention. These should be construed to bemerely illustrative of some of the more prominent features andapplications of the invention. Other beneficial results can be obtainedby applying the disclosed information in a different manner or bymodifying the disclosed embodiments. Accordingly, other aspects and amore comprehensive understanding of the invention may be obtained byreferring to the detailed description of the exemplary embodiments takenin conjunction with the accompanying drawings, in addition to the scopeof the invention defined by the claims.

1. A combine harvester having a crop processing rotor, comprising: apair of opposite facing concaves extending at least partially beneaththe rotor in a circumferential manner and moveable generally in asymmetrical and concentric manner therefrom; and a rockshaft havingrotational movement about its axis and substantially radial movementrelative the rotor, wherein both rotational and radial movement of saidrockshaft causes said pair of concaves pivotally coupled thereon to movein a generally vertical direction to move said pair of concaves towardor away from the rotor.
 2. The combine harvester of claim 1 wherein eachconcave of said pair of concaves substantially simultaneously travelsymmetrical paths relative to one another when said pair of concavesmove toward or away from the rotor.
 3. The combine harvester of claim 1further comprising a guide for movement of said rockshaft in a generallyvertical direction.
 4. The combine harvester of claim 3 wherein saidguide comprises a guide plate having a generally vertical slot formoveably receiving and retaining said rockshaft, wherein said rockshafttranslates up and down in said slot when said pair of concaves movetoward or away from the rotor.
 5. The combine harvester of claim 4wherein said rockshaft slides up and down in said slot.
 6. The combineharvester of claim 4 further comprising a lever pivotally coupled at oneend to said rockshaft and another end pivotally coupled and moveablewithin a generally horizontal slot in said guide plate, said other endof said lever having translational movement in said horizontal slot,wherein said rotational movement of said rockshaft, said translationalmovement of said rockshaft along said vertical slot, in combination withthe translational movement of said other end of said lever in saidhorizontal slot moves said pair of concaves toward or away from therotor in substantially a vertical manner.
 7. The combine harvester ofclaim 6 wherein said rockshaft in said vertical slot is in its lowermostposition when said concaves are in their lowermost position.
 8. Thecombine harvester of claim 6 wherein said other end of said lever insaid horizontal slot is in its lateralmost position relative the rotorwhen said concaves are in their lowermost position.
 9. The combineharvester of claim 6 wherein said rockshaft in said vertical slot is inan uppermost position when said concaves are in their uppermostposition.
 10. The combine harvester of claim 6 wherein said other end ofsaid lever in said horizontal slot is in closest proximity to the rotorwhen said concaves are in their uppermost position.
 11. The combineharvester of claim 6 wherein said slots are substantially perpendicularto one another.
 12. The combine harvester of claim 6 wherein said slotsprovide straight line motion.
 13. The combine harvester of claim 4further comprising a lever having a first pivot corresponding with anaxis of said rockshaft and a second pivot corresponding with an axissubstantially parallel to said axis of said rockshaft, said axis of saidrockshaft having translational movement in a first direction and saidother axis having translational movement in a second direction.
 14. Thecombine harvester of claim 4 wherein said pair of concaves is detachablyand pivotally coupled at said common axial location on said suspensionsystem.
 15. The combine harvester of claim 3 wherein said guidecomprises a guide plate having a generally vertical slot for moveablyreceiving and retaining a guide block coupled to said rockshaft, saidguide block sliding generally up and down in said slot when said pair ofconcaves move toward or away from the rotor.
 16. The combine harvesterof claim 3 wherein said guide includes a generally horizontal slot. 17.The combine harvester 1 wherein said concaves are detachably coupled tosaid rockshaft.
 18. The combine harvester of claim 1 wherein said pairof concaves are pivotally coupled at a common axial location.
 19. Thecombine harvester of claim 1 wherein said pair of concaves istranslationally coupled at separate laterally spaced locations on saidsuspension system.
 20. The combine harvester of claim 19 wherein saidpair of concaves is slidably coupled at said laterally spaced locations.21. The combine harvester of claim 1 wherein said pair of concaves isboth pivotally coupled at a common axial location and translationallycoupled at separate laterally spaced locations for generally radialmovement relative to the rotor.
 22. The combine harvester of claim 1wherein each concave of said pair of concaves is substantiallyidentical.
 23. The combine harvester of claim 1 wherein either concaveof said pair of concaves may be utilized on either side of the rotor.24. The combine harvester of claim 1 wherein said pair of concaves maybe utilized in a side-by-side manner on either side of the rotor. 25.The combine harvester of claim 1 wherein said concaves of a plurality ofpairs of concaves are arranged in both a longitudinal direction and in atransverse direction.
 26. The combine harvester of claim 25 wherein oneof any of said concaves may be removed and exchanged with any other ofsaid concaves in said combine.
 27. The combine harvester of claim 1further comprising a guide assembly having a first portion and a secondportion cooperating with one another to define a guide slot to permittranslational movement of said pair of concaves.
 28. The combineharvester of claim 26 further comprising a pair of axially extendingsupport members alongside the rotor for detachably affixing said pair ofconcaves in spaced proximity to the rotor, slots of a plurality of saidguide assemblies receiving said support members to permit generally onlyup and down sliding movement of said support members.
 29. The combineharvester of claim 28 wherein said first portion includes an upturnedportion and said second portion includes an upturned portion, both saidupturned portions at least partial opposing one another to define saidguide slot when said first and second portions at least partiallyoverlap one another.
 30. The combine harvester of claim 1 furthercomprising a hold down member cooperating with said rockshaft todetachably retain said concaves resting on said rockshaft.
 31. Thecombine harvester of claim 30 wherein said concaves of said pair ofconcaves comprise side rails having distal ends defining acircumferentially extending hook-shaped lug received on said rockshaftto provide pivoting movement of said concaves about said rockshaft. 32.The combine harvester of claim 1 wherein gaps between said pair ofconcaves and the rotor are substantially the same at a top of said pairof concaves and at a bottom of said pair of concaves when said pair ofconcaves are in an open position relative the rotor, and wherein saidgap at said top of said pair of concaves is greater than said gap atsaid bottom of said pair of concaves when said pair of concaves are in aclosed position relative the rotor such that a wedge shaped inlet and awedge shaped outlet are generally defined between said pair of concavesand the rotor when said pair of concaves are in said closed position.for pivoting movement about an axis substantially parallel to an axis ofthe rotor and said pair of cross members coupled to a rockshaft suchthat rotational movement of said rockshaft causes said common axialshaft to move in a generally vertical direction to move said pair ofconcaves toward or away from the rotor.
 33. The combine harvester ofclaim 1 further comprising a spring coupled to said pair of concaves,wherein said spring is compressed when said concaves are moved away fromthe rotor as a foreign object passes between at least one of saidconcaves and the rotor.
 34. A method for a combine harvester havingrotor, said method comprising the steps of: rotating a rotor over aplurality of concaves at least partially positioned underneath therotor; moving said plurality of concaves toward or away from the rotorsuch that said plurality of concaves simultaneously travel symmetricalpaths relative to one another; removing one of said plurality ofconcaves from a first position; and replacing said one concave withanother of said plurality of concaves from a second position.
 35. Themethod of claim 34 further comprising the step of each said concavesubstantially traveling symmetrical paths relative to one another whensaid concaves move toward and away from the rotor when the operatingclearance is adjusted.
 36. The method of claim 34 further comprising thesteps of rocking a rockshaft back and forth to impart movement of saidconcaves toward and away from the rotor, and as a result of said rockingstep, said concaves pivoting about a portion of a circumference of saidrockshaft.
 37. The method of claim 34 further comprising the step ofreplacing said other concave with said one concave in said secondposition.
 38. The method of claim 34 wherein said removing and replacingsteps comprise moving said one concave from one side of the rotor andreplacing said one concave with said other concave from the other sideof the rotor.
 39. The method of claim 34 wherein said removing andreplacing steps comprise moving said one concave from one side of therotor and replacing said one concave with said other concave from saidone side of the rotor.
 40. The method of claim 34 wherein said removingand replacing steps comprise moving said one concave from either side ofthe rotor and replacing said one concave from either side of the rotor.